These investigations will analyze the effectiveness of lectin fractionated haploidentical parental or sibling marrow transplants in treatment of severe combined immunodeficiency or acute leukemia in man. If these investigations prove favorable, this approach will be extended to treatment of other highly lethal hematological and immunodeficiency diseases of man. Bone marrow transplantation in mice will also be investigated as a means to introduce resistance genes for the prevention of AKR leukemia or against the development of Potter myelomas in inbred mice and to prevent and treat autoimmune disease in NZB, NZBx NZW and other autoimmune-prone mice.